Whether or not you have the physical and mental stamina to train with Kelly (who, truth be told, is an awesome and hilarious guy), there’s good reason boxing has zoomed in popularity: it’s an amazing workout. One of the reasons it has become so popular, particularly with models, is because boxers don’t really look to bulk up. “We prefer ripped muscle tone as opposed to bulk. The bulk slows you down and takes away from your speed and fluidity,” explains Kelly.

With that in mind, we asked Kelly to show us how we can use boxing workouts to help sculpt lean, toned arms.

“For sculpting arms, boxers tend to do lots of arm rolls,” says Kelly. “To do arm rolls, just hold your arms out straight, as if you were imitating a flying airplane, and slowly rotate them in small circles. Keep your fingers straight out, too — you want to keep the blood flowing freely. We do them for entire rounds at times [boxing rounds are typically three minutes]. Sometimes we’ll do them with a 2 or 3 pound weight in each hand.”

“Shadow boxing — throwing punches in the air — helps a lot. It’s a good way to get you loose and get your blood flowing; this is also a workout exercise that you can do with 2 or 3 pound weights in your hands for added intensity,” says Kelly. “Try to keep your feet just little more than shoulder width apart. You don’t want to put too much weight on your heel. It’s also important to try to balance the weight on the front foot evenly and to keep the majority of your weight on the ball of your back foot. From there, throw your punches. Keep both hands up by your cheeks and once you throw a punch, bring your hand straight back up to your face to keep you out of danger of counter shots.”

“Lastly, there’s the cardio rope. While it’s not a boxing move per se, it’s a workout exercise that boxers often use to work their shoulders and arms. Same goes for jumping rope,” Kelly explains. “When jumping rope, I notice that a lot of people tend to remain flat footed. Like with shadow boxing, try to operate off the ball of your feet when skipping rope as it will relieve some of the pressure from the cartilage of your knees that comes with the constant jumping up and down. It’s also important to remember to keep your arms as close to your hips as possible because when you spread your arms too much, you make the rope shorter.”

TheFashionSpot's Lifestyle Editor, Sharon Feiereisen, is a freelance lifestyle writer based in New York City. Her work has been published in Newsday, The Knot, AM New York, WHERE New York, Dan's Papers, and Hamptons Magazine, among many other print and online outlets. Check out her tumblr blog, Random Happenings.